# US 9,520,218 B2 · Method of resin-sealing laminated core

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- Number: US 9,520,218 B2
- Document ID: US9520218B2
- Status: Granted
- Kind: B2
- Application number: 14/059,543
- Filed: 2013-10-22
- Published: 2014-05-08
- Granted: 2016-12-13
- Earliest claimed: 2012-11-02
- Assignees: Mitsui High-Tec, Inc.
- Applicants: Mitsui High-tec, Inc.
- Inventors: Hirotoshi Mabu
- Web page: https://patentgrep.com/patent/US9520218B2

## CPC

- H01F 7/0221: {Mounting means for PM, supporting, coating, encapsulating PM}
- H02K 15/03: having permanent magnets
- H02K 1/276: Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
- H02K 2201/09: Magnetic cores comprising laminations characterised by being fastened by caulking
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

A method of resin-sealing for a laminated core includes the steps of: holding by sandwiching a core body 11 between a resin injection mold 20 and a supporting mold 21; extruding a molten resin using a plunger 37 from a resin reservoir pot 24 provided in the resin injection mold 20; and resin-sealing the permanent magnets 18 in the magnet insertion holes 16 and 17, wherein a material of the resin reservoir pot 24 of the resin injection mold 20 and a region through which the resin passes from the resin reservoir pot 24 is a superhard material, and wear in the resin injection mold 20 due to a flow of the resin is reduced. With this, a gap between the resin reservoir pot 24 and the resin injection mold 20 due to a difference in thermal expansion is less easily produced.

## Claims

### Claim 1

A method of resin-sealing for a laminated core, the method comprising the steps of:
holding by sandwiching a core body between a resin injection mold and a supporting mold that face each other, the core body having a plurality of magnet insertion holes in which permanent magnets are respectively inserted;
extruding a molten resin using a plunger from each of resin reservoir pots provided in the resin injection mold; and
resin-sealing the permanent magnets in the magnet insertion holes,
wherein a material of the resin reservoir pot of the resin injection mold and a region through which the resin passes from the resin reservoir pot is a superhard material, and wear in the resin injection mold due to a flow of the resin is reduced,
wherein the superhard material has a hardness HRA 80-100, or above,
wherein the resin injection mold includes a cylindrical body having the resin reservoir pot and the region through which the resin passes and made of the superhard material; and a resin injection mold body supporting the cylindrical body and made of steel,
wherein injection holes are provided inside an outer periphery of the cylindrical body, the injection holes respectively communicating to the magnet insertion holes of the core body,
wherein runners respectively connecting the injection holes and the resin reservoir pots are provided, and
wherein the runners are provided in the bottom of the cylindrical body.

### Claim 2 (depends on 1)

The method of resin-sealing for a laminated core according to claim 1, wherein
connecting portions between the resin reservoir pots and the runners are chamfered in a circular arc cross-section shape.

### Claim 3 (depends on 1)

The method of resin-sealing for a laminated core according to claim 1, wherein the runners are provided on the cylindrical body, and tapered such that a section of the runners decreases from an opening side toward at the bottom of the cylindrical body.

### Claim 4 (depends on 1)

The method of resin-sealing for a laminated core according to claim 1, wherein
the runners are provided on a middle plate disposed between the resin injection mold and the core body.

### Claim 5 (depends on 4)

The method of resin-sealing for a laminated core according to claim 4, wherein
the runners are tapered such that a section of the runners increases toward the resin injection mold.